Question

For animals adapted to it, swimming is energetically the cheapest form of locomotion because of a. the streamlined body forms of aquatic animals. b. the slow speed of locomotion of many swimmers. c. the buoyancy of water. d. a and c only. e. a, b, and c.

Short answer

The correct answer is d. a and c only.

Step-by-step solution

Understanding the terminologies

The streamlined body forms of aquatic animals mean that they have a shape designed to reduce the resistance of the water. This implies that less energy is needed to move through the water. The slow speed of locomotion of many swimmers might reduce the energy used because moving slowly often requires less energy than moving fast. The buoyancy of water helps to support the weight of the animal, reducing the energy needed to support their own weight while moving.

Analysing each choice

Choice a references the streamlined body forms of aquatic animals - this is correct since streamlined body reduces the resistance which in turn lowers energy usage. Choice b is about the speed of locomotion - this depends highly on individual species and cannot be generalized to all animals. Choice c refers to the buoyancy of water - this is correct, as buoyancy reduces the need to spend energy on staying afloat. Choice d and e include a and/or c, making them possible candidates.

Choosing the best answer

Options a and c both valid factors that explain why swimming might be energetically cheap. However, option b cannot be generalized as the speed of locomotion varies among different species. Therefore, the most comprehensive and accurate choice would be option d, which includes both a and c.

Key concepts

Streamlined Body Forms

When observing aquatic animals, one of the most notable features is their sleek, streamlined body shape. This adaptation is not a mere coincidence but an evolutionary answer to the resistance posed by water. A streamlined body minimizes the friction and turbulence created as the animal moves through the water. Just as a sleek racing car is designed to cut through the air with minimal resistance, aquatic animals evolve similarly structured bodies to glide through water more efficiently.

What this translates to in terms of energetics is quite significant. Less energy is spent fighting against drag, and more is used to propel the organism forward. This efficiency is crucial for survival, as it conserves energy for other vital activities such as foraging and reproduction. For example, consider the torpedo-shaped body of a shark or the smooth contours of a dolphin; these are not just aesthetically pleasing but functionally important to reduce energy expenditure during swimming.

Buoyancy of Water

The buoyancy of water is another factor that plays a pivotal role in the energetics of swimming in animals. Buoyancy is the upward force exercised by a fluid, counteracting the weight of an object immersed in it. In the aquatic world, buoyancy substantially reduces the effects of gravity on an animal’s body. This guidance from nature means that aquatic animals do not have to expend as much energy combating their own weight as land animals do.

Consider sea turtles, for instance, they can navigate long distances largely because the water supports their body weight, allowing them to use less energy to maintain their position in the water column. This support system gives them the ability to traverse oceans without the extreme energy costs that would be incurred if they had to continuously struggle against gravity.

Animal Locomotion

The study of animal locomotion encompasses understanding how different animals move through various environments, including aquatic surroundings. Within water, animals employ different modes of locomotion, such as swimming with fins or flippers, undulation, or jet propulsion. Each method involves a precise coordination of the body's musculature, the aquatic environment, and physics.

In the context of swimming, many aquatic animals have evolved specialized appendages, like the flippers of a penguin, which are used in a rowing motion to create thrust. Meanwhile, fish typically use a side-to-side motion called lateral undulation that propels them forward efficiently in water. These methods of locomotion, refined through millions of years of evolution, highlight the adaptability of life and the drive towards optimizing energy use in the relentless quest for survival.

Energy Efficiency in Aquatic Animals

Energy efficiency is critical to the survival of aquatic animals, as the resources in their environments can often be limited or hard to come by. Aquatic animals have evolved a variety of strategies to manage their energy expenditure, thereby improving their chances of survival and reproductive success.

For example, many fish conserve energy by schooling, which reduces resistance for each individual in the group. Additionally, many aquatic animals are poikilothermic, meaning their body temperature and metabolic rate are influenced by the temperature of the surrounding water, which can lead to a reduction in energy requirements during colder temperatures. Moreover, the behavior of floating or riding currents can also reduce energy needed for movement, as seen in jellyfish or drift building larvae. Understanding these strategies is crucial for biologists and environmentalists who strive to preserve the delicate balance of marine ecosystems.